The Argentine was responding to questions about a gesture he made to Neville - indicating that the United player talked too much - after scoring the first of two goals in City's 2-1 first leg win in the all-Manchester League Cup semi-final on Tuesday.
Former England defender Neville had angered Tevez by repeating comments made previously by Ferguson that the Argentine was not worth the fee United would have been forced to pay to keep him last year.
"It was bad of him to say Ferguson was right," Tevez, who cost City around 25 million pounds, told Argentina's Radio Rivadavia in Spanish.
"It seems to me very much (as) sucking his socks to go and talk (to media) about the personal problems I had with Ferguson," he added, using a common Argentine expression for a sycophant.
"This moron, what's he doing talking about me, an ex-team-mate ... That was a lack of respect. I've never said anything about him."
Tevez said he passed right by Neville as he celebrated his first goal, a penalty equaliser, so he turned towards him and made a hand gesture.
It was not clear at the time who Tevez meant the gesture for, but he clarified.
"I would never do that to the fans, that would be showing disrespect."
Tevez said it had been a very tough match and City would have to up their game at Old Trafford next Wednesday.
"We did not play well at our ground, we have to improve a lot for the return," the Argentina striker said.
The 25-year-old, who has scored 13 goals in his last 11 games for City, said he felt his form was coming back to the level of his time at Boca Juniors and Corinthians.
Tevez helped Boca win the Argentine league and South American Libertadores Cup titles and Corinthians lift the Brazilian championship before moving to England in 2006.
